1. Technical Field
The present invention relates to a coil unit suitable for contactless power transmission and an electronic apparatus or the like using the coil unit.
2. Related Art
There is known contactless power transmission that uses electromagnetic induction to transmit power without using a metal contact. As applications of contactless power transmission, charging of a cell phone, charging of a home appliance (e.g., a handset), and the like have been proposed.
A related-art examples of contactless power transmission is JP-A-2006-60909. In JP-A-2006-60909, a resonant capacitor connected to the output of a power transmission driver and a primary coil constitute a series resonant circuit and a power transmission unit (primary) provides power to a power reception unit (secondary).
In recent years, cell phones are required to be downsized further. For this reason, a coil unit for transmitting power must also be further downsized, particularly, in the thickness dimension.
For example, if a foreign object such as a metal piece intrudes into the gap between the primary coil and secondary coil during contactless power transmission, the foreign object generates an eddy current thereby causing heating.